Slade.] ^^ [March 15, 



those of the Arctoidea, but exhibiting less strength than those of the 

 ^luroidea. 



The suborder Pinnipedia is easily separated into three families — the 

 Otaridpe, the Trichecidfe and the Phocidse. The first of these bear genetic 

 relationship to the Ursidoe in many of the cranial characters. The arch 

 is composed, as in the Fissipedia, of three bones. Of these, the jugal 

 presents a wide backward progressing process, which divides into a short 

 upper and a long lower one, receiving and supporting the extended pro- 

 cess of the squamosal, as in a mortise. 



The postorbital processes are well developed. A more or less distinctly 

 marked sagittal crest exists with an extended surface for muscular attach- 

 ment. The coronoid surface of the ascending ramus is wide, but not pro- 

 duced above the level of the arch. 



In the Trichecidfe, of which Trichecus is the single genus, the maxilla 

 enters largely into the formation of the arch, the jugal is shorter and 

 broader than it is in the other ftimilies, and nearly quadrangular, sending 

 up a prolonged postorbital process from its superior border, while pos- 

 teriorly its inferior border underlies the process of the squamosal. The 

 condylar surface of the mandible points backwards, while those of the 

 rounded coronoids are scarcely lifted above the dental series. 



In the Phocidfe, the composition of the arch does not differ essentially 

 from that of the Otaridne, although it is relatively much weaker. There 

 are no postorbital processes, and the sagittal crest is less distinctly 

 marked. The angle of the mandible is not inflected. 



The Chiroptera are divisible into the suborders Maaachiroptera and 

 Microchiroptera. The family Pteropodidoe includes all the characters of 

 the first of these suborders. In Pteropus, the arch is long and relatively 

 slender, and composed of three bones, of which the jugal is splint-like, 

 adliering to the outer and under surface of both the squamosal and maxilla, 

 which meet above it and form the span. 



The postorbilals of the frontal and jugal not unfrequently meet, and 

 thus complete the bony orbit. There are strongly developed crests, both 

 occipital and sagittal. The coronoid surface of the mandible is fitted for 

 large muscular attachments, being high, broad and recurved. The angle 

 is flattened and rounded, presenting an extended surface. Of the six 

 f\imilies into which the suborder Microcliiroptera is divided, the Vesper- 

 tilionidse may be taken as the typical representatives. The arch is slender 

 and complete throughout the entire group, except in some of the Phylosto- 

 midaj, in whom it is entirely wanting. 



When present, the horizontal curvature is large, and the vertical also 

 considerable, the convexity being upwards. In its conformation, it is 

 similar to that of the Pteropodida;. The orbit is incomplete, the temporal 

 fossae are relatively large. The parietal crest is but slightly developed. 

 The mandible is stout and high at the symphysis. The ascending ramus 

 is compressed, and bears a coronoid process which is strongly indented for 

 muscular attachment. Immediately below the condyle, is a backward 



